Simultaneous quantification of chlorogenic acid and taurocholic acid in human plasma by LC-MS/MS and its application to a pharmacokinetic study after oral administration of Shuanghua Baihe tablets

An LC-MS/MS method was developed and validated for the simultaneous quantification of chlorogenic acid(CGA) and taurocholic acid(TCA) in human plasma using hydrochlorothiazide as the internal standard. The chromatographic separation was achieved on a Hedera ODS-2 column with a gradient elution using 10 mmol·L^(-1) of ammonium acetate buffer solution containing 0.5% of formic acid- acetonitrile as mobile phase at a flow rate of 300 μL·min-1. The detection was performed on a triple quadrupole tandem mass spectrometer by multiple reaction monitoring in negative ESI mode. The method was fully validated over the concentration ranges of 0.1–10 ng·m L^(-1) for CGA and 2–150 ng·m L^(-1) for TCA. It was successfully applied to a pharmacokinetic study of CGA and TCA in healthy Chinese volunteers after oral administration of Shuanghua Baihe tablets(SBTs). In the single-dose study, the maximum plasma concentration(C_(max)), time to reach C_(max)(T_(max)) and elimination half-life(t_(1/2)) of CGA were(0.763 8 ± 0.542 0) ng·m L^(-1),(1.0 ± 0.5) h, and(1.3 ± 0.6) h, respectively. In the multiple-dose study, the C_(max), T_(max) and t_(1/2) of CGA were(0.663 7 ± 0.583 3) ng·m L^(-1),(1.1 ± 0.5) h, and(1.4 ± 0.7) h, respectively. For TCA, no significant characteristic increasing plasma TCA concentration-time curve was found in the volunteers after oral administration of SBTs, indicating its complicated process in vivo as an endogenous ingredient.

Differential expression of cholangiocyte and ileal bile acid transporters following bile acid supplementation and depletion

AIM: We have previously demonstrated that cholangiocytes, the epithelial cells lining intrahepatic bile ducts,encode two functional bile acid transporters via alternative splicing of a single gene to facilitate bile acid vectorial transport. Cholangiocytes possess ASBT,an apical sodium-dependent bile acid transporter to take up bile acids,and t-ASBT,a basolateral alternatively spliced and truncated form of ASBT to efflux bile acids.Though hepatocyte and ileal bile acid transporters are in part regulated by the flux of bile acids, the effect of alterations in bile acid flux on the expression of t-ASBT in terminal ileocytes remains undear.Thus,we tested the hypothesis that expression of ASBT and t-ASBT in cholangiocytes and ileocytes was regulated by bile acid flux. METHODS: Expression of ASBT and t-ASBT message and protein in cholangiocytes and ileocytes isolated from pair- fed rats given control (C) and 1% taurocholate (TCA) or 5% cholestyramine (CY) enriched diets,were assessed by both quantitative RNase protection assays and quantitative immunoblotting.The data obtained from each of the control groups were pooled to reflect the changes observed following TCA and CY treatments with respect to the control diets. Cholangiocyte taurocholate uptake was determined using a novel microperfusion technique on intrahepatic bile duct units (IBDUs) derived from C,TCA and CY fed rats. RESULTS: In cholangiocytes,both ASBT and t-ASBT message RNA and protein were significantly decreased in response to TCA feeding compared to C diet.In contrast, message and protein of both bile acid transporters significantly increased following CY feeding compared to C diet.In the ileum,TCA feeding significantly up-regulated both ASBT and t-ASBT message and protein compared to C diet,while CY feeding significantly down-regulated message and protein of both bile acid transporters compared to C diet.As anticipated from alterations in cholangiocyte ASBT expression,the uptake of taurocholate in microperfused IBDUs derived from rats on TCA diet decreased 2.7-fold,whereas it increased 1.7-fold in those on CY diet compared to C diet fed groups. CONCLUSION: These data demonstrate that expression of ASBT and t-ASBT in cholangiocytes is regulated by a negative feedback loop while the expression of these transporters in terminal ileum is modified via positive feedback.Thus, while transcriptional regulatory mechanisms in response to alterations in bile acid pool size are operative in both cholangiocytes and ileocytes,each cell type responds differently to bile acid supplementation and depletion.

Effects of octreotide on acute necrotizing pancreatitis in rabbits

AIM:To assess the role of oxygen-derived free radicals and cytokines in the pathogenesis of taurocholic acid-induced acute pancreatitis,and to evaluate the preventive effects of octreotide towards the development of acute pancreatitis. METHODS:Acute pancreatitis was induced in male New Zealand white rabbits by retrograde injection of 0.8 mL/kg·b.m,of 50 g/L sodium taurocholate (NaTC) in the pancreatic duct.Sham- operated animals served as control.Octreotide i mg/kg·b.m. was administered subcutaneously before the induction of pancreatitis.Blood was taken from the jugular vein before and at 1,3,6,12 and 24 h after pancreatitis induction. Serum activities of amylase,IL-6 and TNF-α and levels of malonyl dialdehyde (MDA),glutathione (GSH),glutathione peroxidase (GPx),catalase and superoxide dismutase (Mn-, Cu-,and Zn-SOD) in pancreatic tissue were measured. RESULTS:Serum TNF-α and IL-6 levels increased significantly 3 h after the onset of pancreatitis,and then returned to control level.The tissue concentration of MDA was significantly elevated at 24 h,while the GSH level and GP-x,catalase,Mn-SOD,Cu-,Zn-SOD activities were all significantly decreased in animals with pancreatitis as compared to the control.Octreotide pretreatmnent significantly reversed the changes in cytokines and reactive oxygen metabolites.Octreotide treatment did not alter the serum amylase activity and did not have any beneficial effects on the development of histopathological changes. CONCLUSION:Oxygen-derived free radicals and proinflammatory cytokines are generated at an early stage of NaTc-induced acute pancreatitis in rabbits.Prophylactic octreotide treatment can prevent release of cytokines and generation of reactive oxygen metabolites,but does not have any beneficial effects on the development of necrotizing pancreatitis.

Epidural anaesthesia restores pancreatic microcirculation and decreases the severity of acute pancreatitis

AIM： To investigate the effect of epidural anaesthesia （EA） on pancreatic microcirculation during acute pancreatitis （AP）. METHODS： AP was induced by injection of sodium taurocholate into the pancreatic duct of Sprague-Dawley rats. To realize EA, a catheter was introduced into the epidural space between T7 and T9 and bupivacaine was injected. Microcirculatory flow was measured by laser Doppler flowmetry. Arterial blood gas analyses were performed. At the end of the experiment （≤ 5 h）, pancreas was removed for histology. The animals were divided into three groups： Group 1 （n =9）, AP without EA, Group 2 （n = 4）, EA without AP; and Group 3 （n = 6）, AP treated by EA. RESULTS： In Group 1, pancreatic microcirculatory flow prior to AP was 1414, 39 perfusion units （PU）. After AP, microcirculatory flow obviously decreased to 9 4-6 PU （P〈0.05）. Metabolic acidosis developed with base excess （BE） of - 14 4, 3 mmol/L. Histology revealed extensive edema and tissue necrosis. In Group 2, EA did not significantly modify microcirculatory flow. BE remained unchanged and histological analysis showed normal pancreatic tissue. In Group 3, AP initially caused a significant decrease in microcirculatory flow from 155 ± 25 to 11± 7 PU （P〈0.05）. After initiation of EA, microcirculatory flow obviously increased again to 81±31 PU （P〈0.05）. BE was -6±4 retool/L, which was significantly different compared to Group 1 （P〈0.05）. Furthermore, histology revealed less extensive edema and necrosis in pancreatic tissue in Group 3 than that in Group 1. CONCLUSION： AP caused dramatic microcirculatory changes within the pancreas, with development of metabolic acidosis and tissue necrosis. EA allowed partial restoration of microcirculatory flow and prevented development of tissue necrosis and systemic complications. Therefore, EA should be considered as therapeutic option to prevent evolution from edematous to necrotic AP.

Oral nano-formulation improves pancreatic islets dysfunction via lymphatic transport for antidiabetic treatment

Type 2 diabetes mellitus(T2DM)therapy is facing the challenges of long-term medication and gradual destruction of pancreatic isletβ-cells.Therefore,it is timely to develop oral prolonged action formulations to improve compliance,while restoringβ-cells survival and function.Herein,we designed a simple nanoparticle with enhanced oral absorption and pancreas accumulation property,which combined apical sodiumdependent bile acid transporter-mediated intestinal uptake and lymphatic transportation.In this system,taurocholic acid(TCA)modified poly(lactic-co-glycolic acid)(PLGA)was employed to achieve pancreas location,hydroxychloroquine(HCQ)was loaded to execute therapeutic efficacy,and 1,2-dilauroyl-sn-glycero-3-phosphocholine(DLPC)was introduced as stabilizer together with synergist(PLGA-TCA/DLPC/HCQ).In vitro and in vivo results have proven that PLGA-TCA/DLPC/HCQ reversed the pancreatic islets damage and dysfunction,thus impeding hyperglycemia progression and restoring systemic glucose homeostasis via only once administration every day.In terms of mechanism PLGA-TCA/DLPC/HCQ ameliorated oxidative stress,remodeled the inflammatory pancreas microenvironment,and activated PI3K/AKT signaling pathway without obvious toxicity.This strategy not only provides an oral delivery platform for increasing absorption and pancreas targetability but also opens a new avenue for thorough T2DM treatment.